This was common back then. The PDP-8 had eight primary instructions, although one of them was multi-purpose. This helped keep the hardware simple when we didn't

This was common back then. The PDP-8 had eight primary instructions, although one of them was multi-purpose. This helped keep the hardware simple when we didn't have ICs. RISC isn't about having a small ISA but about a regular, orthogonal instruction set.